''METHOD FOR ATTACHING A SET OF CHIP PARTS, LEAD PARTS AND SHIELD CASES FOR PREVENTING A HIGH FREQUENCY SIGNAL FROM BEING LAKED TO PRINTED CIRCUIT BOARD"

Abstract

A method of attaching a lead part and a shield case for preventing a high-frequency signal from being leaked to a printed circuit board according to the present invention, includes a solder coating step of coating solder so that the solder should cover the whole of an aperture provided through a printed circuit board into which a lead of the lead part is inserted and so that said solder should cover a part of an aperture provided through the printed circuit board into which an engagement portion of the shield case is inserted, a mounting step of inserting the lead of the lead part and the engagement portion of the shield case into the respective apertures to thereby mount the lead part and the shield case on the printed circuit board, and a soldering step of inserting the printed circuit board mounted with the lead part and the shield case into a reflowing furnace and melting the solder to thereby carry out soldering.

Full Text

METHOD FOR ATTACHING LEAD PARTS AND SHIELD CASE TO PRINTED
CIRCUIT BOARD, AND METHOD FOR ATTACHING CHIP PARTS riEAD PARTS AND-SHIELD CASE TO PRINTED CIRCUIT-BOARD
BACKGROUND
1. Field of the Invention:
The present invention relates to a method for
attaching a lead part and a shield case to a printed circuit board and a method for attaching a chip part, a lead part and a shield case to a printed circuit board.
2. Background of the Invention:
A conventional method for attaching a lead part and
its shield case to a printed circuit board and a conventional method for attaching a chip part, a lead part and a shield case to a printed circuit board will next be described with reference to FIGS. 1A to lj.
A process shown in FIG. 1A will first be explained.
Reference numeral 1 designates a printed circuit board. A wiring pattern (not shown) is formed on at least one face (an
va
upper side face in FIG. 1A) of the printed circuit board. A aperture 1h and a slit Is are formed in this printed circuit board 1. A lead 4L of each of plural lead parts (only one lead part 4 is shown in FIGS. 1A to 1J) 4 described later is inserted into the aperture 1. The printed circuit board 1 is cut and the plural lead parts 4 and chip parts 2 corresponding to these plural lead parts 4 are soldered to the individual printed

circuit board 1. One portion of a shield case 5 is fitted into the slit Is.
A cream solder is printed to one portion of
predetermined plural pairs of wiring patterns on the one face of such a printed circuit board 1 by using a soldering printer. Plural chip parts (only one chip part is shown in FIGS. 1A to 1J) 2 is mounted onto each printed cream solder (not shown in the figure) by using a mounting device. The printed circuit board 1 mounting these plural chip parts 2 thereonto is put in a reflow furnace and is heated. The solder is melted and is then cooled. Thus, the plural chip parts 2 are soldered to one portion of the plural pairs of wiring patterns of the printed circuit board 1.
Processes of FIGS. IB and 1C will next be explained.
In the process of FIG. IB, a solder 3 is coated on one portion of the wiring patterns on one face of the printed circuit board 1 by using a solder coating device in the vicinity of the aperture In into which the lead 4L of each of the plural lead parts 4 is inserted. In the process of FIG. 1C, the printed circuit board 1 is reversed such that the one face of the printed circuit board 1 is located on a lower side as shown in FIG. 1C.
In a process of FIG. ID, the plural lead parts 4 are
mounted onto the other face (an upper side face in FIG. ID) of the printed circuit board 1 such that the lead 4L of each of the plural lead parts 4 is inserted into the aperture In of the
printed circuit board 1 manually or using a mounting inserting device. Each lead 4L enters the solder 3 on the one face of the printed circuit ;board 1.
In a process of FIG. 5E, the printed circuit board 1
on which mounted are the plural lead parts 4 is put in the reflow furnace and is heated. Thus, the solder 3 is melted and is then cooled. Thus, the plural lead parts 4 are soldered to one portion of predetermined wiring patterns of the printed circuit board 1 together with the plural chip parts 2.
In a process of FIG. IF, the printed circuit board 1
is cut and divided by using a substrate divider at every plural lead parts 4 and chip parts 2 respectively corresponding to these plural lead parts.
In a process of FIG. 1G, a shield case 5 is fitted
and attached to an individual printed circuit board 1 to which the lead parts 4 and the chip parts 2 corresponding to these lead parts 4 are respectively soldered.
After the process of FIG. 1G, plural individual
assembly blocks each attaching the shield case 5 thereto are positioned at a predetermined position of a carrier and are attached so that the assembly blocks are formed. This process is not shown in FIG. 5.
In a process of FIG. 1H, a portion of a claw 5N
described later as one portion of the shield case 5 of each of the plural individual printed circuit boards 1 on the carrier and one portion of a land constructed by a conductive layer on
one face of each of the individual printed circuit boards 1 are respectively coated with solder 6 by using the solder coating device.
In a process of FIG. II, the claw 5N of the shield
case 5 of each of the plural individual printed circuit boards 1 on the carrier is folded on a side of each of the individual printed circuit boards 5 by using a clincher.
After the process of FIG. II, the plural individual
assembly blocks are detached from the carrier although this detachment is not illustrated in this figure.
In a process of FIG. 1J, the individual assembly
blocks are reversed and are put in the reflow furnace and are heated. Thus, the solder 6 is melted and is then cooled. Thus, it is possible to obtain a circuit block in which the shield case 5 is soldered to each of the individual printed circuit boards 1 having the soldered chip parts 2 and the soldered lead parts 4. In addition to the soldering of the shield case, leads of a through capacitor of a case assembly, connector terminals, etc. are also similarly soldered. For example, this circuit

block is a high frequency block formed of a tuner and an intermediate frequency amplifier.
This conventional method for attaching the lead part
and its shield case to the printed circuit board has the following drawbacks.
The soldering process of leads of the lead parts to
the wiring pattern of the printed circuit board and the shield
case thereto using the reflow furnace is a separate process so that the number of processes is increased.
Each of the individual printed circuit boards must be
attached to the carrier when a portion between a claw of one portion of the shield case and a land of each of the printed circuit boards is coated with the solder by the solder coating device to solder the shield case to each of the individual printed circuit boards. Further, each of the individual printed circuit boards must be detached from the carrier when each of the printed circuit boards and the shield case are put in the reflow furnace to melt the solder. Accordingly, the number of processes is increased.
When each of the plural individual printed circuit
boards attaching the shield case thereto is attached to the carrier and the portion between the claw of one portion of the shield case and the land on a side of the slit Is of each of the printed circuit boards is coated with the solder by the solder coating device, drawbacks exist in that it is difficult to set
attaching and coating conditions and a coating accuracy is low.
A slanting cut nozzle or a special nozzle is required
as a nozzle for coating the solder around the shield case in the solder coating device. Accordingly, there is also a drawback of an increase in price of the solder coating device.
A portion between the land of a printed circuit board
and the claw of the shield case is coated with the solder by inserting the nozzle for coating the solder into the shield
case. Further, portions between the wiring pattern of the printed circuit board and leads of a through capacitor, connector terminals, etc. are coated with the solder such that the leads and the terminals, etc. are inserted into the nozzle. Accordingly, the nozzle is floated, damaged, etc. Therefore, problems exist in that repair works must be required and a manufacturing line is stopped and so on.
SUMMARY OF THE INVENTION In view of such aspects, it is an object of the
present invention to provide a method for attaching a lead part and a shield case to a printed circuit board and a method for attaching a chip part, a lead part and a shield case to a printed circuit board in which the numbers of processes and works can be reduced in comparison with the conventional attaching method and a solder coating accuracy for soldering the printed circuit board and the shield case can be improved.
According to an aspect of the present invention, a
method of attaching a lead part and a shield case for preventing a high-frequency signal from being leaked to a printed circuit
board includes a solder coating step of coating solder so that
said solder should cover the whole of an aperture provided through a printed circuit board into which a lead of the lead part is inserted and so that the solder should cover a part of an aperture provided through the printed circuit board into which an engagement portion of the shield case is inserted, a mounting step of inserting the lead of the lead part and the engagement portion of the shield case into the respective
apertures to thereby mount the lead parts and the shield case on the printed circuit board, and a soldering step of inserting the printed circuit board mounted with the lead part and the shield case into a reflowing furnace and melting the solder to thereby carry out soldering.
In accordance with such a construction of the present
invention, the plural lead parts and the plural shield cases are simultaneously soldered to the printed circuit board by the ref1ow furnace.
The first invention includes a process in which a
solder is coated on one portion of a wiring pattern in a vicinity of each aperture of a printed circuit board for inserting each lead of plural lead parts thereinto and on a land formed of a conductive layer in a vicinity of a slit for inserting one portion of each of plural shield cases respectively corresponding to the plural lead parts thereinto; a process in which each lead of the plural lead parts extends through each aperture of the printed circuit board, the one portion of each of the plural shield cases extends through the

slit of the printed circuit board so as to surround each of the plural lead parts and the lead parts and the shield cases are mounted onto the printed circuit board; a process in which the printed circuit board mounting the plural lead parts and the plural shield cases thereonto is put in a reflow furnace and the solder is melted and is then cooled, and each lead of the plural lead parts and the one portion of each of the plural shield cases are soldered to the one portion of the wiring pattern of
the printed circuit board and to the land; and a process for obtaining plural individual circuit blocks by cutting and dividing the printed circuit board at every set of each of the lead parts and each of the shield cases. Accordingly, in comparison with the conventional attaching method, no carrier is used at a solder coating time prior to reflow. Further, solder coating for soldering the plural lead parts and the plural shield cases to the printed circuit board and solder melting using the reflow furnace are respectively simultaneously performed. Accordingly, the number of processes and works can be reduced. Since no carrier is used, it is possible to obtain an attaching method of a lead part and a shield case to the printed circuit board in which a solder coating accuracy for soldering the printed circuit board and the shield case can be improved. Therefore, the scale of an attaching plant is reduced and a working space can be reduced. Further, since no carrier is used, a nozzle used in the solder coating for soldering the shield case to the printed circuit board can be constructed by a flat nozzle in which an opening is approximately perpendicular to a longitudinal direction of the nozzle. Accordingly, the price of a solder coating device can be reduced.
In accordance with the second invention, a connector
is arranged in each of the plural shield cases in the attaching method of a lead part and a shield case to the printed circuit board in the first invention. Further, the plural circuit blocks constructed by the plural lead parts, the plural shield cases and the plural connectors are located at every pair so as
to arrange circumferential faces of the respective connectors in proximity to each other, and the pairs of circuit blocks are attached to the printed circuit board so as to arrange the pairs of circuit blocks in a zigzag shape approximately in parallel with each other. Accordingly, effects similar to those in the first invention are obtained. Further, it is possible to obtain an attaching method of a lead part and a shield case to the printed circuit board in which blanking efficiency of the printed circuit board with respect to the circuit blocks constructed by the lead parts, the shield cases and the connectors can be improved.
The third invention includes a process for soldering
a chip part to one portion of a wiring pattern of a printed circuit board; a process in which a solder is coated on one portion of a wiring pattern in a vicinity of each aperture of the printed circuit board for inserting each lead of plural lead parts thereinto and on a land made of a conductive layer in a vicinity of a slit for inserting one portion of each of plural shield cases respectively corresponding to the plural lead parts thereinto; a process in which each lead of the plural lead parts extends through each aperture of the printed circuit board, the one portion of each of the plural shield cases extends through the slit of the printed circuit board so as to surround each of the plural lead parts, and the lead parts and the shield cases are mounted onto the printed circuit board; a process in which the printed circuit board mounting the plural lead parts and the plural shield cases thereonto is put in a reflow furnace, the
solder is melted and is then cooled, and each lead of the plural lead parts and the one portion of each of the plural shield cases are respectively soldered to the one portion of said wiring pattern of the printed circuit board; and a process for obtaining plural individual circuit blocks by cutting and dividing the printed circuit board at every set of each of the lead parts and each of the shield cases.
Accordingly, in comparison with the conventional attaching method, no carrier is used at a solder coating time prior to reflow. Further, solder coating for soldering the plural lead parts and the plural shield cases to the printed circuit board and solder melting using the reflow furnace are respectively simultaneously performed. Accordingly, the number of processes and works can be reduced. Since no carrier is used, it is possible to obtain an attaching method of a chip part, a lead part and a shield case to the printed circuit board in which a solder coating accuracy for soldering the printed circuit board and the shield cases can be improved. Therefore, the scale of an attaching plant is reduced and a working space can be reduced. Further, since no carrier is used, a nozzle used in the solder coating for soldering the shield case to the printed circuit board can be constructed by a flat nozzle in which an opening is approximately perpendicular to a longitudinal direction of the nozzle. Accordingly, the price of a solder coating device can be reduced.
In accordance with the fourth invention, a connector
is provided in each of the plural shield cases in the attaching
method of a chip part, a lead part and a shield case to the printed circuit board in the third invention. Further, the plural circuit blocks constructed by the plural chip parts, the plural lead parts, the plural shield cases and the plural connectors are located at every pair so as to arrange circumferential faces of the respective connectors in proximity to each other, and the pairs of circuit blocks are attached to the printed circuit board so as to arrange the pairs of circuit I locks in a zigzag shape approximately in parallel with each other. Accordingly, effects similar to those in the third invention are obtained. Further, it is possible to obtain an attaching method of a chip part, a lead part and a shield case to the printed circuit board in which blanking efficiency of the printed circuit board with respect to the circuit blocks constructed by the chip parts, the lead parts, the shield cases and the connectors can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 1J are diagrams used to explain a conventional attaching method;
Figs. 2A to 2H are diagrams used to explain processes according to an embodiment of the present invention;
FIG. 3A is a plan view showing a surface of a printed circuit board on which a wiring pattern (not shown) is formed;
FIG. 3B is a plan view showing the printed circuit board shown in FIG. 3A in a state that a case and a connector are inserted thereinto;
FIGS. 3C and 3D are schematic diagrams showing the
shape of a claw of a shield case;
FIGS. 4A to 4F are diagrams showing process each showing one portion of the embodiment in an enlarged scale; and
FIG. 5 is a schematic diagram showing a printed circuit board in which circuit blocks in the embodiment are arranged.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A method for attaching a lead part and a shield case
to a printed circuit board and a method for attaching a chip part, a lead part and a shield case to a printed circuit board according to an embodiment of the present invention will next be described with reference to FIGS. 2A to 2H.
A process of FIG. 2A will first be explained.
Reference numeral 1 designates a printed circuit board. A wiring pattern (not shown) is formed on at least one face (an upper side face in FIG. 2A) of the printed circuit board 1. A aperture Ih and a slit Is are bored through this printed circuit board 1. A lead 4L of each of plural lead parts (only one lead parts 4 is shown in FIGS. 2A to 2H) 4 described later is

inserted into the aperture (each aperture is formed in each of one portion of plural wiring patterns) Ih. One portion of each of plural shield cases 5 respectively corresponding to the plural lead parts 4 and described later is inserted into the slit Is.
A cream solder is printed to one portion of
predetermined plural pairs of wiring patterns on one face of the
printed circuit board 1 by using a soldering printer. Plural chip parts 2 (only one chip part 2 is shown in FIGS. 2A to 2H) are mounted onto each printed cream solder (not shown in the figure) by using a mounting device. The printed circuit board 1 mounting these plural chip parts 2 thereonto is put in a reflow furnace and is heated. The solder is melted and is then cooled. Thus, the plural chip parts 2 are soldered to the one portion of the predetermined wiring patterns of the printed circuit board
Processes of FIGS. 2B and 2C will next be explained.
In the process of FIG. 2B, solders 3 and 6 are respectively coated on a portion of the wiring pattern on one face of the printed circuit board having the aperture Ih into which each of leads of the plural lead parts 4 is inserted, and as shown in FIGS. 4A and 4B, on a land (an island-shaped conductive layer formed on the printed circuit board 1) L (see FIG. 4B) so as to slightly project into the slit Is on an inner side of the slit Is for inserting one portion of a shield case 5 described later thereinto by using a solder coating device. In the process of FIG. 1C, the printed circuit board 1 is reversed such that the one face of the printed circuit board 1 is located on a lower side in this figure (see FIG. 4C).
Next, in a process of FIG. 2D, the plural lead parts
4 are mounted onto the other face (an upper side face in FIG. ID) of the printed circuit board 1 manually or using a mounting device such that each of the leads 4L of the plural lead parts 4 is inserted into the aperture Ih of the printed circuit board 1.
Each of the leads 4L enters the solder 3 on the one face of the printed circuit board 1.
Next, in a process of FIG. 2E, the shield case 5 is
fitted into the printed circuit board 1 such that a portion of a claw 5N as one portion of the shield case 5 is inserted into the slit Is of the printed circuit board 1.
As shown in FIG. 5 which shows the printed circuit
board 1 seen from the side of the lead parts 4, in this example, one pair of shield cases 5 are arranged such that one portions of circumferential faces of respective connectors CN are opposed to each other and four sets of such a pair are arranged in a zigzag shape on one printed circuit board 1. Therefore, blanking efficiency of one printed circuit board 1 is improved and eight shield cases 5 can be attached to this one printed circuit board 1. The distance between slits inserting the shield cases 5 therein on the printed circuit board 1 and corresponding to adjacent corner portions of the adjacent shield cases 5 on the printed circuit board 1 is secured so that the strength of the printed circuit board 1 between the slits is

increased. In FIG. 4, illustrations of the lead parts 4, the chip parts 2 and a fine shape of the printed circuit board 1 are omitted.
A claw 5N shown in each of FIG. 3C or 3D and FIG. 4D
is formed in one portion of the shield case 5 inserted into the slit Is of the printed circuit board 1. In FIG. 3D, a concave portion into which one portion of the printed circuit board 1,
i.e., a connection portion 1CN is inserted is formed on a side of the claw 5N of the shield case 5. In FIG. 3C, this concave portion into which the connection portion 1CN is inserted is not formed. FIG. 3A is a plan view showing a surface of a printed circuit board 1A on which a wiring pattern (not shown) is formed. A substantially rectangular slit Is into which the shield case 5 is to be inserted is formed through the printed circuit board 1, and the connection portion 1CN of the printed circuit board 1 is formed at a part of the slit Is. In FIG. 3A, reference numeral Ih depicts an aperture for a connector. FIG. 3B is a plan view showing the printed circuit board 1 in a state that the case 5 is inserted into the slit Is thereof and the connector CN formed integrally with the case 5 is inserted into the connector aperture In. In this embodiment, of seven claws 5N, four claws 5N have respective concave portions into which the connector portions 1CN shown in FIG. 3D are inserted.
Next, in a process of FIG. 2F, a playing end portion
of the claw 5N is bent inside by using a clincher (see FIG. 3E). This process is omitted when there is no claw 5N in one portion of the shieldx case 5.
Next, in a process of FIG. 2G, the eight shield cases
5 are attached to the one printed circuit board 1. The printed circuit board 1, in which at least one chip parts 2 and at least one lead part 4 are attached into each of these eight shield cases 5, is put in the reflow furnace and is heated so that the solders 3 and 6 are melted. Thereafter, the solders 3, 6 are cooled. Thus, a portion between each of the leads 4L of the

eight lead parts 4 and one portion of each of the wiring patterns of the printed circuit board 1, and a portion between the claw 5N (one portion of the shield case 5 when there is no claw 5N) as one portion of each of the eight shield cases 5 and the lend L of the printed circuit board 1 are soldered.
In a process of FIG. 2H, the printed circuit board 1
is cut by a substrate divider in the vicinity of the slit Is (see FIG. 4F) so that eight circuit blocks each having at least one chip part 2, at least one lead part 4 and the shield case 5 soldered to the individual printed circuit board 1 are obtained. For example, each of these circuit blocks is a high frequency block formed of a tuner and an intermediate frequency amplifier.
Having described a preferred embodiment of the present invention with reference to the accompanying drawings, it is to be understood that the present invention is not limited to the above-mentioned embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit or scope of the present invention as defined in the appended claims.

WE CLAIM
1. A method of attaching a lead part and a shield

case for preventing a high-frequency signal from being leaked to a printed circuit board, comprising the steps of:
(a) a solder coating step of coating solder so that
said solder should cover the whole of an aperture provided
through a printed circuit board into which a lead of said lead
part is inserted and so that said solder should cover a part of
an aperture provided through said printed circuit board into
which an engagement portion of said shield case is inserted;
(b) a mounting step of inserting said lead of said
lead part and said engagement portion of said shield case into
said respective apertures to thereby mount said lead part and
said shield case on said printed circuit board; and
(c) a soldering step of inserting said printed
circuit board mounted with said lead part and said shield case
into a reflowing furnace and melting said solder to thereby
carry out soldering.

2. An attaching method according to claim 1, wherein
in said mounting step plural sets of lead parts and shield cases
are mounted on said printed circuit board and said mounting step
further comprises a step of cutting said printed circuit board
at every shield case after said soldering step.
3. An attaching method according to claim 2, wherein

said shield case is provided with a connector, and said plural sets of shield cases are mounted on said printed circuit board alternately with their surfaces where connectors are provided being opposed one another.
4. An attaching method according to claim 1, wherein
in said solder coating step, a claw is provided on the
engagement portion of said shield case used for soldering and
said solder is coated on a part of an aperture which is formed
through said printed circuit board and into which said claw is
inserted.
5. An attaching method according to claim 4, wherein
before said soldering step, a free end portion of said claw
provided on one end of the engagement portion of said shield
case to be inserted into said printed circuit board is bent
inward.
6. A method of attaching a chip part, a lead part and
a shield case for preventing a high-frequency signal from being
leaked to a printed circuit board, comprising the steps of:

(a) a chip-part soldering step of soldering the chip
part on said printed circuit board;
(b) a solder coating step of coating solder so that
said solder should cover the whole of an aperture provided
through said printed circuit board into which a lead of said
lead part is inserted and so that said solder should cover a
part of an aperture provided through said printed circuit board into which an engagement portion of the shield case is inserted;
(c) a mounting step of inserting said leads of said
lead part and said engagement portion of said shield case into
said respective apertures to thereby mount said lead parts and
said shield case on said printed circuit board; and
(d) a soldering step of inserting said printed
ircuit board mounted with said lead part and said shield case
into a reflowing furnace and melting said solder to thereby
r-arry out soldering.
7. An attaching method according to claim 6, wherein
in said mounting step plural sets of lead parts and shield cases
are mounted on said printed circuit board and said mounting step
further comprises a step of cutting said printed circuit board
at every shield case after said soldering step.
8. An attaching method according to claim 7, wherein
said shield case is provided with a connector, and said plural
sets of shield cases are mounted on said printed circuit board
alternately with their surfaces where connectors are provided
being opposed one another.
9. An attaching method according to claim 6, wherein
in said solder coating step, a claw is provided on the
engagement portion of said shield case for soldering and said
solder is coated on a part of an aperture which is formedthrough said printed circuit board and into which said claw is inserted.
10. An attaching method according to claim 9, wherein
before said soldering step, a free end portion of said claw
provided on one end of the engagement portion of said shield
case to be inserted into said printed circuit board is bent
nward.
11. An apparatus for attaching a lead part and a
shield case' for preventing a high-frequency signal from being
leaked to a printed circuit board, comprising:
a solder coating means for coating solder so that said solder should cover the whole of an aperture provided through a printed circuit board into which a lead of said lead part is inserted and so that said solder should cover a part of an aperture provided through said printed circuit board into which an engagement portion of said shield case is inserted;
a mounting means for inserting said lead of said lead part and said engagement portion of said shield case into said respective apertures to thereby mount said lead part and said shield case on said printed circuit board; and
a soldering means for inserting said printed circuit board mounted with said lead part and said shield case into a reflowing furnace and melting said solder to thereby carry out soldering.12. An apparatus for attaching a chip part, a lead part and a shield case for preventing a high-frequency signal from being leaked to a printed circuit board, comprising:
a chip-part soldering means for soldering the chip part on said printed circuit board;
a solder coating means for coating solder so that said solder should cover the whole of an aperture provided through said printed circuit board into which a lead of said Lead part is inserted and so that said solder should cover a part of an aperture provided through said printed circuit board into which an engagement portion of the shield case is inserted;
a mounting means for inserting said leads of said lead part and said engagement portion of said shield case into said respective apertures to thereby mount said lead parts and said shield case on said printed circuit board; and
a soldering means for inserting said printed circuit board mounted with said lead part and said shield case into a reflowing furnace and melting said solder to thereby carry out soldering.